U.S. patent application number 14/491303 was filed with the patent office on 2015-03-19 for tracking external markers to internal bodily structures.
The applicant listed for this patent is ProNova Solutions, LLC. Invention is credited to Jonathan Huber, Niek Schreuder.
Application Number | 20150080634 14/491303 |
Document ID | / |
Family ID | 52668564 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150080634 |
Kind Code |
A1 |
Huber; Jonathan ; et
al. |
March 19, 2015 |
TRACKING EXTERNAL MARKERS TO INTERNAL BODILY STRUCTURES
Abstract
Systems and methods of tracking location of an internal bodily
structure of a patient in a radiation treatment room, including a
fiducial marker having a unique center point, an offset structure
detachably connected to the fiducial marker, the offset structure
having unique three dimensional offset coordinates relative to the
center point, a means for detachably mounting the offset structure
to the patient, an imaging unit to measure location information of
the offset structure relative to a target internal bodily structure
of the patient, and a detection unit to detect location information
of the offset structure and to calculate an offset distance between
the target internal bodily structure and the center point.
Inventors: |
Huber; Jonathan; (Knoxville,
TN) ; Schreuder; Niek; (Knoxville, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ProNova Solutions, LLC |
Knoxville |
TN |
US |
|
|
Family ID: |
52668564 |
Appl. No.: |
14/491303 |
Filed: |
September 19, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61879873 |
Sep 19, 2013 |
|
|
|
Current U.S.
Class: |
600/1 |
Current CPC
Class: |
A61N 5/1049 20130101;
A61N 2005/1059 20130101; A61B 2034/2055 20160201; A61N 5/1075
20130101; A61N 2005/1087 20130101; A61B 90/39 20160201; A61B
2090/3983 20160201; A61N 2005/1058 20130101 |
Class at
Publication: |
600/1 |
International
Class: |
A61N 5/10 20060101
A61N005/10; A61B 19/00 20060101 A61B019/00 |
Claims
1. A system to track location of an internal bodily structure of a
patient in a radiation treatment room, comprising: a fiducial
marker having a unique center point; an offset structure detachably
connected to the fiducial marker, the offset structure having
unique three dimensional offset coordinates relative to the center
point; a means for detachably mounting the offset structure to the
patient; an imaging unit to measure location information of the
offset structure relative to a target internal bodily structure of
the patient; and a detection unit to detect location information of
the offset structure and to calculate an offset distance between
the target internal bodily structure and the center point.
2. The system of claim 1, wherein the radiation treatment room is a
proton therapy treatment room, and the detection unit is mounted to
a proton beam nozzle of the proton therapy treatment room such that
the detection unit detects an air gap between the proton beam
nozzle and the patient.
3. The system of claim 1, further comprising a camera unit to
detect location information of the detection unit relative to the
offset structure.
4. The system of claim 1, wherein the detection unit is one of an
infrared detector, ultrasound detector, camera unit, or microwave
detector.
5. The system of claim 1, further comprising means for obtaining a
gating pattern during movements of the patient and comparing the
gating pattern to corresponding movements of the offset
structure.
6. A method of tracking location of an internal bodily structure of
a patient in a radiation treatment room, comprising: providing a
fiducial marker having a unique center point; mounting an offset
structure to the fiducial marker, the offset structure having
unique three dimensional offset coordinates relative to the center
point; coordinating the unique center point of the fiducial marker
with a radiation isocenter of the treatment room; mounting the
offset structure to a patient; measuring location information of
the offset structure relative to a target internal bodily structure
of the patient; and measuring location information of the offset
structure; and calculating an offset distance between the target
internal bodily structure and the center point based on the
location information of the offset structure.
7. The method of claim 6, wherein the radiation treatment room is a
proton therapy treatment room, the method further comprising:
mounting the detection unit to a proton beam nozzle of the proton
therapy treatment room; and detecting an air gap between the proton
beam nozzle and the patient using the detection unit.
8. The method of claim 6, further comprising detecting location
information of the detection unit relative to the offset
structure.
9. A system to track location of an internal bodily structure of a
patient in a radiation treatment room, comprising: an imaging unit
to measure offset coordinates between an external 3-d structure of
the patient and an internal bodily structure of the patient
relative to a radiation isocenter of the treatment room; and a
detection unit to detect location information of the 3-d structure
and to calculate an offset distance between the target internal
bodily structure and the isocenter using the location information
of the 3-d structure.
10. A method of tracking location of an internal bodily structure
of a patient in a radiation treatment room, comprising: measuring
offset coordinates between an external 3-d structure of the patient
and an internal bodily structure of the patient relative to a
radiation isocenter of the treatment room; detecting location
information of the 3-d structure; and calculating an offset
distance between the target internal bodily structure and the
isocenter using the location information of the 3-d structure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/879,873, filed on Sep. 19, 2013, the
disclosure of which is incorporated herein in its entirety by
reference.
FIELD OF INVENTION
[0002] The present general inventive concept relates to systems and
methods of tracking the location of an internal bodily structure of
a patient using external markers.
BACKGROUND
[0003] In some medical applications such as proton therapy (PT), it
is desirable to track the location of target areas in the human
body. For regions of the human anatomy that move, for example due
to breathing or heartbeat, it is important to take such motions
into consideration, when computing the effect of the motion on the
treatment plan being generated. PT is a cancer treatment technology
that uses high energy protons to penetrate a patient's body and
deposit energy into treatment volumes such as cancerous tumors. The
charged protons may be generated in a particle accelerator,
commonly referred to as a cyclotron and/or a synchrotron, and
directed to the patient in the form of a beamline using a series of
magnets that guide and shape the particle beamline such that the
particles penetrate the patient's body at a selected location and
are deposited at the site of the treatment volume. Particle therapy
leverages the Bragg Peak property of charged particles such that
the majority of the energy is deposited within the last few
millimeters of travel along the beamline--at a point commonly
referred to as the isocenter, as opposed to conventional, intensity
modulated radiation therapy (i.e., photons) in which the majority
of energy is deposited in the first few millimeters of travel, and
the radiation can pass beyond the target region, thereby
undesirably damaging healthy tissue.
[0004] Fiducial markers have been used in the past, in order to
track target regions of the anatomy. Fiducials-based tracking can
be difficult for a patient, for a number of reasons. For example,
high accuracy tends to be achieved by using bone-implanted fiducial
markers, but implantation of fiducials into a patient is generally
painful and difficult. Less invasive techniques such as
skin-attached markers have been used, but such systems are
typically less accurate, especially when the target area is moving,
for example during respiration or heart beating of the patient. In
some methods that use gating to handle anatomical motion, dynamic
tracking may be achieved by establishing a relationship between
internally implanted fiducials, and externally placed markers that
are tracked in real time. Multiple doses of radiation are often
used to track the location of a target area for treatment.
[0005] Target positioning through imaging guidance is important for
the accurate delivery of radiation treatment. It is challenging to
verify that the imaging, localization, and targeting systems are
aligned with the true radiation isocenter. Accordingly, systems and
methods of tracking internal structures that are less invasive,
more accurate, less time consuming, and more effective would be
desirable.
BRIEF DESCRIPTION OF THE FIGURES
[0006] The following example embodiments are representative of
example techniques and structures designed to carry out the objects
of the present general inventive concept, but the present general
inventive concept is not limited to these example embodiments. In
the accompanying drawings and illustrations, the sizes and relative
sizes, shapes, and qualities of lines, entities, and regions may be
exaggerated for clarity. A wide variety of additional embodiments
will be more readily understood and appreciated through the
following detailed description of the example embodiments, with
reference to the accompanying drawings in which:
[0007] FIG. 1 illustrates an external fiducial marker configured in
accordance with an example embodiment of the present general
inventive concept;
[0008] FIG. 2 illustrates a proton therapy treatment room during an
isocenter set-up phase according to an example embodiment of the
present general inventive concept;
[0009] FIGS. 3A and 3B illustrate a proton therapy treatment room
during patient set-up and operational phases according to an
example embodiment of the present general inventive concept;
and
[0010] FIG. 4 illustrates a proton therapy treatment room
configured in accordance with an example embodiment of the present
general inventive concept.
DETAILED DESCRIPTION
[0011] Reference will now be made to the example embodiments of the
present general inventive concept, examples of which are
illustrated in the accompanying drawings and illustrations. The
example embodiments are described herein in order to explain the
present general inventive concept by referring to the figures.
[0012] Various example embodiments of the present general inventive
concept provide systems and methods of tracking the location of an
internal bodily structure of a patient. These systems and methods
may help to provide accurate tumor localization, and may be used to
deliver radiation beams to the target tumor with minimal x-ray
invasions.
[0013] Embodiments of the present general inventive concept provide
various tumor localization techniques to precisely determine the
location of tumor(s) to help ensure that an effective dose of
radiation is delivered to the tumor(s), while sparing healthy,
non-cancerous tissue. On-board imaging technologies such as single
and stereoscopic x-ray imaging, kilovoltage and megavoltage CT
imaging, implantable fiducial markers and transponders, ultrasound
imaging, MRI, and others may help to improve the efficacy of proton
or other radiation therapy by gathering tumor location information
such that a radiation beam may be specifically targeted at the
tumor region. Various proton beam-shaping techniques may also be
used to help direct radiation precisely at the tumor(s) to be
treated, while reducing the radiation exposure to surrounding
tissue.
[0014] In some embodiments, a Cone Beam Computed Tomography (CBCT)
imaging system can be used to deliver 3-d images to permit
registration between a 3-d reference image and a 3-d current image,
improving precision of patient positioning. The CBCT can also be
moved to a specific position and take a flat, digital x-ray image
for confirmation images. Diagnostic imaging modalities may be
integrated, initially to support academic research advancing proton
therapy methods.
[0015] Digital x-ray, using an x-ray tube source and flat x-ray
panels, are commonly used to image patients. These systems are
quick to image and give a relatively low radiation dose to the
patient for each image. However, the baseline image used for
registration (alignment of the patient images with the planning
image) is a 3-D image from the planning CT, so there can be a loss
of fidelity when attempting to register 2-D images with the 3-D
baseline. Two orthogonal x-rays may be taken to register in two
different views. Two x-rays at an oblique angle can be used to
create a single, stereoscopic image for registration.
[0016] Imaging with orthogonal x-rays gives the patient an
additional dose of radiation which is roughly 0.2% of the proton
therapy dose.
[0017] CBCT can be used to produce a 3-D image with lower soft
tissue contrast than the diagnostic CT used for planning. The image
from CBCT can be used for the purpose of registration.
[0018] Imaging with CBCT gives the patient an additional dose of
radiation. For a typical, two-field treatment CBCT delivers in
x-ray dose roughly 0.7% of the proton therapy dose, or about three
times the dose associated with a pair of planar x-rays.
[0019] Diagnostic CT can be used to reproduce the fidelity of the
planning CT image. Imaging with DXCT has the disadvantage of higher
dose to the patient. At about 12 times the dose associated with
planar x-rays, over the treatment period the patient will receive
about 3% of the proton therapy dose in additional x-ray dose, a
value large enough to warrant inclusion in treatment planning.
[0020] In some embodiments, an alternative to imaging the patient
with DXCT at every treatment is to use a more conservative imaging
approach for daily use, and image the patient infrequently on DXCT,
timing to be set by the interval for re-planning treatment. This
can be accomplished by including two imagers on the gantry or by
adding the DXCT to the treatment room as an accessory, using the
Patient Positioning Subsystem to present the patient to the DXCT.
CT-on-rails can work with a couch which does not move. Another
option is to do infrequent DXCT imaging in another location.
However, if the CT is done in conjunction with PET scanning to
image the location of delivered radiation (see Section 0 below0
below), imaging while the patient is still on the PPS may be
desirable.
[0021] Magnetic Resonance Imaging sends magnetic fields into the
patient to reconstruct internal structures. MRI allows for patient
tracking during setup without radiation exposure. Additionally, it
can be used in conjunction with PET for doseless range
verification.
[0022] A Vision System can be implemented that uses a camera to
locate the patient via pixel coordinates from a camera. If the
registered pixels change, it can be determined that the patient has
moved. This external structure can be overlaid with the internal
x-ray image to perform patient motion tracking.
[0023] Infrared Tracking (IR) can be used to track external
structures of the patient or an external fiducial. As the IR beam
bounces from the external structure back to the sensor, the time
can then be used to create a 3D location of the structure. If the
patient external structure moves (or the fiducial on the patient)
then the patient positioning system can adjust accordingly. This
patient tracking determines patient movement without additional
radiation exposure.
[0024] Inertial motion units (IMU) sensors can include, among other
things, accelerometers, magnetometers, and gyroscopes that measure
changes in the rotational forces being applied to the sensor. The
vectors obtained can then be used for reverse kinematics to
determine the translational changes to the sensor. Here, the
sensors can be used to detect and quantify patient motion without
additional radiation exposure.
[0025] Both Ultrasound and Microwave imaging technologies provide
information about the patient's internal structures without
exposing the patient to radiation.
[0026] For example, ultrasound imaging can use high frequency waves
(e.g., 1-7 MHz) to detect density differences between hard and soft
tissues. An Ultrasound piezo transducer coupled with
electromagnetic (EM) tracking, vision system tracking,
interferometer tracking, or equivalent tracking technology can
create a 3D reconstruction of the patient's internal tissue. Once
the tumor's position relative to hard tissue has been located via
x-ray, CBCT, or DXCT image then the hard tissue can be located with
the Ultrasound transducer without additional radiation.
[0027] Microwave imaging uses higher frequency waves (1-5 GHz) to
detect dielectric differences between various soft tissues. In
cases where Ultrasound cannot definitively discern between soft
tissue and a tumor, Microwaves can due to the higher water content
of a tumor compared to the surrounding tissue. This higher water
content raises the dielectric constant such that the tumor can be
located within the patient. Similar to Ultrasound, the Microwave
transducer can be tracked without radiation.
[0028] In addition to standard transducers, embodiments of the
present general inventive concept can implement treatment specific
probes. For instance, Prostate treatments can involve insertion of
a saline filled rectal balloon. A small, EM tracked Microwave probe
can be inserted inside this balloon to locate the tumor in real
time. Such techniques can be applied with Ultrasound except the
device may be tracking internal hard tissue instead of the tumor
itself.
[0029] For some general applications, a 3D tracked Ultrasound probe
can be placed externally on the patient near the tumor. Once an
x-ray image has been collected, this probe (or array of probes) can
track the location of the hard tissue and provide tracking of the
tumor without additional radiation exposure.
[0030] FIG. 1 illustrates an external fiducial marker configured in
accordance with an example embodiment of the present general
inventive concept. Although the present general inventive concept
contemplates the use of any 3-d surface of the patient to track the
location of tumors, some embodiments utilize an external fiducial
marker, such as the example fiducial marker illustrated in FIG. 1,
to assist the location calculus.
[0031] As illustrated in FIG. 1, an example embodiment of the
present general inventive concept can include an external fiducial
marker 10 configured to provide an accurate and efficient means of
determining radiation isocenter 14 coincidence with the isocenters
of image guided systems. The fiducial marker 10 can include an
offset structure which in this embodiment comprises a plurality of
detachable fingers 12 detachably coupled to the fiducial marker via
a detachment member. The detachment member can take various forms
chosen with sound engineering judgment, for example a mechanical
and/or magnetic interlocking structure to precisely locate and
secure the offset structure 12 and marker 10 in an appropriate
orientation one to the other. The fingers 12 are configured in
shape and size to provide a unique 3-d offset reference to the
center point 14 of the fiducial 10 which can be mapped to the
isocenter of the proton delivery system. A variety of other shapes
and sizes could be chosen using sound engineering judgment in
addition to a `finger` configuration as illustrated herein to
represent and determine a true radiation isocenter corresponding to
isocenter 14 of the marker 10.
[0032] As illustrated in FIG. 2, the fiducial marker 10 can be
placed on the patient bed 20 within a proton therapy treatment room
200 during an isocenter set-up phase. The patient bed can include a
mounting structure or receptacle to receive the fiducial marker 10
to relate the isocenter to a predetermined location of the patient
bed. The treatment room can include a gantry 26 to rotate a proton
beam nozzle 24 about a patient to be positioned on the patient bed
20. The example treatment room environment of FIG. 2 includes a
detection unit 25, such as, but not limited to, an infrared
detector 25, positioned on the proton beam nozzle 24, to detect
relative position information of the marker 10 and fingers 12
relative to the isocenter of the marker. An optional camera unit 22
may also be provided in the treatment room to detect location
information of components.
[0033] As illustrated in FIGS. 3A and 3B, once the radiation
isocenter has been established by detecting the fiducial marker 10,
a patient 30 can be located on the bed 20, and the offset structure
(e.g., detachable fingers) 12 can be placed on the patient. A
variety of means can be provided to locate and secure the
detachable fingers 12 to a desired location of the patient.
Non-limiting examples include a mounting belt having an
electro/mechanical interlocking device to receive and orient the
offset structure as desired. A variety of other means for placing
the offset structure 12 on the patient could be implemented using
sound engineering judgment without departing from the broader scope
of the present general inventive concept.
[0034] Once the offset structure is mounted to the patient, an
x-ray or other image of the patient can be taken to determine
location information of a tumor 32 relative to the offset structure
12. The detector unit can include a processor having a calculation
module comprising various electronic components, switches and/or
solid state modules configured to compare and manipulate the
location information of the tumor 32 and offset structure 12 so as
to determine three dimensional coordinates of the tumor and offset
structure 12 in order to determine offset coordinates (e.g., h, d,
w) between the tumor and offset structure, enabling an operator or
robotic machine to move the patient bed and/or nozzle an
appropriate amount corresponding to the offset coordinates h, d, w,
such that the isocenter of the tumor 32 can be aligned with the
radiation isocenter 14 (see, e.g, FIG. 1) of the proton therapy
system based on the location of the offset structure 12 relative to
the isocenter of the proton delivery system. It is noted that
offset coordinates `h` and `d` are shown in the 2-dimensional
rendering of FIG. 3A, but it is understood that a third dimension
`w` (in and out of page) could also be provided to provide true
3-dimensional offset coordinates between tumor 32 and offset
structure 12, relative to the isocenter 14.
[0035] Since the detection unit 25 (e.g., infrared detector) is
located on the proton beam nozzle 24, it is possible to measure the
air gap between the patient and the nozzle 24, without the
necessity of having a treatment assistant enter the treatment room
to check and verify the air gap.
[0036] Moreover, embodiments of the present general inventive
concept enable gating patterns to be obtained by a series of CT's
(e.g., fluoroscopy), which can be compared to and/or predicted from
a pattern of movements of the external fiducial marker (or other
3-d patient surface) during patient respiration or other anatomical
movements.
[0037] FIG. 4 illustrates a proton therapy treatment room 200a
configured in accordance with another example embodiment of the
present general inventive concept. As illustrated in FIG. 4, the
detection unit 25 can be floating in space to enable location
flexibility of the detection unit 25. For example, in some
embodiments, the detection unit can be an infrared detector 25 to
determine location information of the fiducial marker 10, 12, and
the camera unit 22 can be used to capture location information of
the infrared detector. Accordingly, once the x-ray unit captures
the location of the tumor relative to the marker 12, it is possible
to calculate the relative location of the fiducial marker to the
tumor, thus knowing where everything is.
[0038] It is noted that the simplified diagrams and drawings do not
illustrate all the various connections and assemblies of the
various components, however, those skilled in the art will
understand how to implement such connections and assemblies, based
on the illustrated components, figures, and descriptions provided
herein, using sound engineering judgment.
[0039] Numerous variations, modifications, and additional
embodiments are possible, and accordingly, all such variations,
modifications, and embodiments are to be regarded as being within
the spirit and scope of the present general inventive concept. For
example, ultrasound, microwave, or other known or later developed
technology could be used instead of IR (infrared) to achieve the
same or similar results. Microwave transducers could be placed on
the patient's body to obtain relative location information to the
tumor using microwaves.
[0040] In addition, regardless of the content of any portion of
this application, unless clearly specified to the contrary, there
is no requirement for the inclusion in any claim herein or of any
application claiming priority hereto of any particular described or
illustrated activity or element, any particular sequence of such
activities, or any particular interrelationship of such elements.
Moreover, any activity can be repeated, any activity can be
performed by multiple entities, and/or any element can be
duplicated.
[0041] While the present general inventive concept has been
illustrated by description of several example embodiments, it is
not the intention of the applicant to restrict or in any way limit
the scope of the inventive concept to such descriptions and
illustrations. Instead, the descriptions, drawings, and claims
herein are to be regarded as illustrative in nature, and not as
restrictive, and additional embodiments will readily appear to
those skilled in the art upon reading the above description and
drawings.
* * * * *